1. Field of the Invention
The invention relates to a switch, more particularly to an electronic switch that is mountable on a circuit board.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional electronic switch 10, as disclosed by the applicant in Taiwanese Patent No. 155965, includes a top cover 11, a conductive ball 12 disposed in the top cover 11, a base 13, and four terminals 14. The top cover 11 is made of plastic, and has a cover main wall 111, and four interconnected sidewalls 112 extending downwardly from a peripheral end of the cover main wall 111. The cover main wall 111 and the sidewalls 112 cooperatively define a chamber 113 having a bottom opening 114. The conductive ball 12 is disposed in the chamber 113. The base 13 is made of plastic, and is inserted into the chamber 113 so as to close the bottom opening 114, thereby confining the conductive ball 12 within the chamber 113. The base 13 has top and bottom surfaces, and four spaced-apart through holes 131 extending through the top and bottom surfaces.
The terminals 14 are inserted respectively into the through holes 131 by a jig (not shown) so as to position the terminals 14 in the respective through holes 131. An epoxy resin 15 is filled within a space defined among the sidewalls 112 of the top cover 11, a bottom surface of the base 13, and the terminals 14, after which an assembly of the top cover 11, the base 13, and the terminals 14 is sent to an oven (not shown) so as to cure the epoxy resin 15, thereby obtaining the conventional electronic switch 10.
Although the aforementioned conventional electronic switch 10 can achieve its intended purpose, during heating of the assembly of the top cover 11, the base 13, and the terminals 14 in the oven, air in the chamber 113 expands when subjected to the high temperature of the oven, and escapes out of the electronic switch 10 through the epoxy resin 15. As a consequence, the epoxy resin 15 is formed with cracks 16, and the surface thereof is rough. Not only is the appearance of the electronic switch 10 affected, but also, the watertight capability of the electronic switch 10 is adversely affected due to the presence of the cracks 16. Hence, the electronic switch 10 gets moist easily, ultimately leading to reductions in the quality and service life of the electronic switch 10.